As a melt bonding device for intermittently sealing a belt-shaped worked sheet, there is the one which is disclosed in the patent document PTL 1. The worked sheet is comprised from a thermoplastic resin etc., while the melt bonding device is a heat seal device. Further, the heat seal device is provided with a facing pair of seal blocks (having functions of press and anvil). The belt-shaped worked sheet is passed between one seal block and the other seal block. Further, by making the heated seal blocks approach each other in the state where the belt-shaped worked sheet has stopped and gripping and pressing the worked sheet from the top and bottom, the sheet is heat sealed (hot melt bonded). Further, the seal blocks are separated from each other and the grip on the worked sheet is released after the heat sealing to thereby end the heat sealing step. After that, the worked sheet is conveyed by a predetermined distance and stopped for the next heat sealing step.
When the seal blocks attempt to separate from the worked sheet after heat sealing, sometimes the worked sheet will not separate from the seal blocks and therefore the worked sheet will be lifted up while stuck to the seal blocks. In that case, if the worked sheet is attempted to be conveyed after the end of the heat sealing step, part of the stuck part (sealed part) will sometimes peel off and the stuck part (sealed part) will be damaged.
Further, a melt bonding device 80 separate from the melt bonding device of PTL 1 is shown in FIG. 6. The worked sheet S2 is comprised of two nonwoven fabrics S1 and a fiber bundle F1. The worked sheet S2 is the same as the multilayer web S2 which is shown in FIG. 4. At the surface of the worked sheet S2 facing the press 81, a fiber bundle F1 is formed. Further, the melt bonding device 80 is comprised of a press 81 and an anvil 82. The press 81 and the anvil 82 respectively have pressing-use projections 81a and support-use projections 82a. 
Further, when the press 81 attempts to separate from the worked sheet S2 after heating sealing, the pressing-use projections 81a of the press 81 sometimes will not separate from the fiber bundle F1 of the worked sheet S2 and will lift it up while stuck to it. (A fiber bundle by nature more easily sticks at the time of heating compared with nonwoven fabrics.) In that case, part of the fibers will peel off from the sealed part or the group of fiber inside of the fiber bundle F1 will be broken up and just part of the fibers will be lifted up. This results in the inherent functions and form of the fiber bundle being remarkably impaired and makes the final product worthless in commercial value. Further, when the worked sheet is conveyed after the end of the heat sealing step, the melt bonded part (sealed part) will sometimes be damaged.